Development of a macromolecular diffraction resource at CHESS, the Cornell High Energy Synchrotron Source will be continued. This resource devises novel x-ray diffraction techniques and apparatus, suitable for the study of macromolecules and macrmolecular assemblies such as enzymes, hormones, immunoglobulins, membranes and membrane components, DNA and DNA-protein complexes, ribosomes, and plant, insect and mammalian viruses, in the form of single crystals, fibers, membranes and solutions. Techniques exploit the unique features of a synchrotron x-ray source: its intensity, its polychromatic nature, and its time structure. The Laue technique for time-resolved crystallography will be developed further using both a new focussed white beam line and a high energy undulator; novel x-ray optical components will be devised; a new form of sensitive, low noise x-ray detector, the Kodak storage phosphor detector, will be evaluated; and an x-ray wiggler beam line optimized for macromolecular crystallography, especially of viruses, will be installed. The last will be incorporated into a Biohazards Facility suitable for handling concentrated solutions and crystals of Pathogenic viruses at the BL3 level in the NIH/CDC classification. To our knowledge, it will be unique in the world. These facilities will continue to be made widely available to scientists from university, government and industry who are interested in macromolecular diffraction as a probe of structure and function.